The present invention generally relates to a wire feed assembly for use in a wire terminating apparatus for making electric harnesses, and more particularly to wire feed mechanisms that simultaneously effect the feeding of harness wires and align their leading ends of the harness wires during assembly of the harnesses.
Certain apparatus for making wire harnesses are known in the art for producing wire harnesses having a plurality of wires of a given constant length with electrical connectors terminated to opposing ends of the harness wires, typically by crimping. Such apparatus includes a multiple wire supply in the form of a series of wire reels with each wire reel having a selected amount of wire wound thereon; a wire measuring and feeding unit for uncurling a predetermined length of wire from each wire reel; two connector terminating assemblies for terminating electrical connectors to the opposing ends of the wires fed from the wire measuring and feeding unit, and a wire holding-and-shifting unit for carrying the predetermined length of wires to the connector terminating assemblies.
Specifically, such apparatus further includes a wire-pulling device as part of the wire measuring and feeding unit for pulling a predetermined length of the harness wires. The wire-pulling device typically comprises a means for pinching the leading ends of the electric wires fed by the wire measuring and feeding unit and a means for moving the wire-pinching means forward and backward. In operation, the wire-pinching means moves forward to pinch the leading ends of the wires fed from the wire measuring and feeding unit and then it moves backward with pinched wires to pay out the predetermined length of harness wires. The length of harness wires fed from the wire measuring and feeding unit is then determined in terms of the distance between the forward and backward movements of the wire-pinching means.
As one may expect, this prior art wire-pulling device requires that the rate at which wires are fed out by the wire measuring and feeding unit be equal to the rate at which the wires are pulled out by the wire-pulling device. Otherwise, electric wires would loosely sag or otherwise be broken. It is difficult to synchronize the wire measuring and feeding unit with the wire-pulling and it cannot be effected quickly, thus preventing wires from being pulled out at an increased rate. This disadvantageously decreases the efficiency with which wire harnesses may be made.
The lateral spacing of the harness wires, i.e., the wire-to-wire interval, must be adjusted to meet the particular connectors used to terminate the harness wires at the wire end. In some instances, as shown in FIG. 12 hereof, the diverging ends L.sub.1 of the wires 1 appear on the downstream side of the wire measuring and feeding unit, as indicated at C. After cutting the wires to provide harness wires of a desired length, these diverging wire ends sections are put in initial linear position as shown in FIG. 13. As seen from FIG. 13, the outermost wires have a longer end lengths L.sub.2 and the wire end lengths decrease inwardly to L.sub.1. This wire end irregularity deleteriously affects termination of connectors to the wires and thereby prevents the harness assembly from promptly continuing in the wire harness workpath unless the ends of the wires are cut to regular lengths. If the length of the cut wires is not substantially uniform some of the shortened wires of the wire harness (i.e., the inner ones as shown in FIG. 12) would fail to be caught by an associated connector during assembly of the harness.
The present invention provides a means to overcome this disadvantage and thereby increase the efficiency of manufacture.